1. Field of the Invention
The present invention relates to golf clubs and associated apparatus used to measure the dynamics of a golfer's swing. More particularly, the present invention relates to golf club apparatus useful in deriving the specific flex or bend of a golf club shaft to provide optimum storage of energy for release as the clubhead meets the ball near the bottom of a downward golf swing as derived from the clubhead speed generated by a given golfer and measured near the bottom of the downward golf swing.
The amount of energy that can be stored within a flexing golf club shaft is proportional to the sustained acceleration that a given golfer can achieve. This sustained acceleration can be related through the apparatus of this invention to clubhead speed at the golf ball striking position at or near the bottom of the downward golf swing. Thus, the apparatus of the invention correlates measured clubhead speed to the specific shaft flex required for each golf club within a set of clubs for any given golfer.
2. Description of the Prior Art
Various factors or characteristics of a golf club are known to be of importance in customizing or matching a set of clubs to an individual golfer. Swing weight, and such factors as static weight, fit of the grip and flexibility of the shaft all have an effect on a golf swing of an individual.
It is well known to weigh golf clubs, both for purposes of determining the club's static weight and the swing weight. U.S. Pat. No. 2,595,717 to K. Smith and U.S. Pat. No. 3,577,771 to K. Solheim show as their primary purpose measurement of the static weight and swing weight of a set of clubs to fit an individual golfer's needs. It is common to adjust the static and swing weights in order to "groove" a swing. Specifically adjusting the flexibility of a shaft to an individual's swing speed has seldom been considered or done previously.
Flexibility of a golf club shaft is a factor that has been used in customizing a set of golf clubs to a specific player. R. Carroll, et al., U.S. Pat. No. 3,180,308 shows a gauge mounted at a grip of a golf club, the guage interconnected by an elongated arm to the clubhead. Upon swinging the club an indicator is moved and retains a flex distance setting at the point of maximum deflection resulting from flexure of the shaft during the golf swing. A flat brace is used to connect the outer end of the club head with the shaft at a point reasonably distant from the shaft in I. Palmer, U.S. Pat. No. 687,540. The purpose of the brace is to prevent the tendency of the clubhead to twist when the ball is struck, yet not hinder the resiliency or flexibility of the shaft.
The inertia of a swinging golf club is measurable by any one of a number of apparatus, one such apparatus seen in U.S. Pat. No. 4,2l2,193 to J. Turley. This moment of inertia may be thought of as the torque applied to accelerate the golf club to a maximum velocity. R. Adams, U.S. Pat. No. 1,953,916 measures the inertia of a golf club, in order to establish the swing weight, by a static measurement. Other swinging golf club testing devices include W. Wettlaufer, U.S. Pat. No. 2,108,877 and J. Crouch, et al., U.S. Pat. No. 3,371,523. Again, the primary, if not sole, purpose of the various testing devices is to measure the swing weight of a given golf club in an attempt to reach an ideal swing weight and then equalize swing weights among various clubs. The swing weight is varied, depending on the results of the tests, by varying the weight at the clubhead. Within limits, varying clubhead weight increases or decreases the amount of flex of a given golf club shaft during the dynamic action of a golf swing.
Other golf clubs useful in improving one's golf swing are seen in N. Mattison, U.S. Pat. No. 1,676,270, which gives an audible sound indicating a consistent swing, and R. Kunihisa, U.S. Pat. No. 3,318,602, used to effectively guage the length of the putting stroke and power behind the stroke.
None of the prior art correlates clubhead speed at impact with the ball to derive shaft flex or measures golf club shaft flexibility through a single club having an adjustable flex shaft. Neither does the prior art show any method for using clubhead speed and golf club shaft flexiblity to make a set of golf clubs for an individual golfer matched to that golfer's specific clubhead speed. Many adjustments to golf clubs in prior art consist of varying clubhead weight upon a given shaft. The apparatus of this invention provides for the standardization of clubhead weights for each club within a set, and for varying the golf club shaft flexibility as required to specifically match a given golfer's clubhead speed. Existing manufacturing techniques rely on static weighing and measuring processes during fabrication. The apparatus of this invention provides for correlating the dynamics of a golfer's swing into the fabrication of golf clubs.